I need more Bacteroidetes

There is an interesting article in Nature this month describing a study from Washington University in St. Louis that showed obese folks have a different microbial flora in the gut than leaner subjects. This was attributed to the fatter people having greater numbers of organisms in a family called Firmicutes. Evidently these organisms are more efficient in converting complex carbohydrates into sugars which are absorbed by the intestines and converted to fat. If your gut is blessed with greater numbers of Bacteroidetes, on the other hand, the carbohydrates are excreted to a greater extent and sugars which can be converted to fat are not as plentiful.
This suggests some attractive approaches to countering weight gain through manipulation of the gut flora. Surely that would be more fun than a diet and more exercise.